Patent Literature 1 listed below describes an electronic device such as a mobile phone that transmits air-conduction sound and bone-conduction sound to a user. Patent Literature 1 also describes that the air-conduction sound is sound perceived by an auditory nerve of a user as a result of an eardrum being vibrated by an air vibration that is created by a vibration of an object and that travels through an external auditory canal down to the eardrum. Furthermore, Patent Literature 1 describes that bone-conduction sound is transmitted to the auditory nerve of the user through a part of a user's body (e.g. a cartilaginous portion of an external ear) that is in contact with the vibrating object.
According to Patent Literature 1, in the described mobile phone, a rectangular plate-shaped vibration body configured by piezoelectric bimorph and a flexible material is attached to an outer surface of a housing via an elastic member. Patent Literature 1 also describes that, upon application of a voltage to the piezoelectric bimorph of the vibration body, the piezoelectric material is expanded and contracted in a longitudinal direction, thereby causing the vibration body to undergo flexture vibration. As a result, when the user places the vibration body in contact with an auricle, air-conduction sound and bone-conduction sound are transmitted to the user.